Method of producing aqueous dispersions as a base for hot sealing adhesives

Abstract

Poly(meth)acrylate dispersions, comprised of: (A) 50-90 wt. % methacrylic acid esters; (B) 5-30 wt. % acrylic acid alkyl esters; [lit., "acrylic acid acrylic esters"]; (C) 2-10 wt. % of another functionalized monomer; (D) 2-10 wt. % of a radically polymerizable carboxylic acid or a polycarboxylic acid or a partially esterified polycarboxylic acid; and (E) 0-40 wt. % of a monomer which is copolymerizable with components (A) to (D).

What is claimed is:  
     
       1. A method of priming a metal surface, comprising: 
       applying an aqueous polymer dispersion on a surface of a metal;  
       wherein said aqueous dispersion comprises a particulate poly(meth)acrylate comprising the following monomeric components:  
       (A) 50-90 wt. % of a methacrylic acid alkyl ester;  
       (B) 5-30 wt. % of an acrylic acid alkyl ester having a glass transition temperature Tg in the range of −20 to 50° C. and having formula I:                    
       wherein R 1  represents an alkyl, aryl, or alkaryl group having 2-10 C atoms;  
       (C) 2-10 wt. % of a functionalized monomer of formula II:                    
       wherein R 2  represents hydrogen or methyl; and R 3  represents a glycidyl group                    
       or an alkyl group which has 2-6 C atoms and is substituted with at least one hydroxyl group;  
       (D) 2-10 wt. % of at least one radically polymerizable carboxylic acid or a polycarboxylic acid or a partially esterified polycarboxylic acid; and  
       (E) 0-40 wt. % of other monomers which are copolymerizable with (A) to (D);  
       wherein, in the process of preparation, in a first polymerization stage, monomers (A) to  
       (C) and optionally (E) are copolymerized;  
       wherein in a second polymerization stage, monomers (A), (B), (D) and optionally (E) are copolymerized; and  
       wherein the sum of the amounts of monomers (A) to (E) is 100 wt. % in each polymerization stage.  
     
     
       2. The method according to  claim 1 , wherein said metal surface is a surface of an aluminum sheet, an aluminum foil, an iron sheet or an iron foil. 
     
     
       3. The method according to  claim 1 , wherein the monomer of formula I is n-butyl acrylate. 
     
     
       4. The method according to  claim 1 , wherein the monomer of formula II is glycidyl (meth)acrylate or hydroxy(meth)acrylate. 
     
     
       5. The method according to  claim 1 , wherein said monomer (E) is styrene, C 1 -C 4  alkylstyrene or cycloalkyl (meth)acrylate. 
     
     
       6. The method according to  claim 1 , wherein said applying is a method selected from the group consisting of spraying, brushing, pouring, dipping, blade-coating and roll-coating. 
     
     
       7. The method according to  claim 1 , further comprising: 
       drying of said metal surface after said applying of said aqueous polymer dispersion, thereby obtaining a dried coating.  
     
     
       8. The method according to  claim 7 , wherein said dried coating has a thickness of from 2 to 10 microns. 
     
     
       9. The method according to  claim 7 , wherein said drying occurs at a temperature of from 100 to 200° C. 
     
     
       10. The method according to  claim 7 , wherein a drying time is from 5 seconds to 5 minutes. 
     
     
       11. The method according to  claim 1 , wherein a methacrylate content of the monomers polymerized in said first polymerization stage is about 60±20 wt % based on a total weight of monomers (A) to (C) and (E). 
     
     
       12. The method according to  claim 1 , wherein a content of the monomer of formula (I) polymerized in said first polymerization stage is about 30±10 wt % based on a total weight of monomers (A) to (C) and (E). 
     
     
       13. The method according to  claim 1 , wherein a content of the monomer of formula (II) polymerized in said first polymerization stage is about 10±15 wt % based on a total weight of monomers (A) to (C) and (E).